[PATCH] D36996: [X86] Prevent several calls to ISD::isConstantSplatVector from returning a narrower APInt than the original scalar type

[Chandler Carruth via Phabricator via llvm-commits]

chandlerc accepted this revision.
chandlerc added a comment.
This revision is now accepted and ready to land.

LGTM, minor nits below, feel free to submit whenever.



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Comment at: include/llvm/CodeGen/SelectionDAGNodes.h:88
   /// undefined, return true and return the constant value in \p SplatValue.
-  bool isConstantSplatVector(const SDNode *N, APInt &SplatValue);
+  /// This returns the smallest possible splat unless AllowShrink is set to
+  /// false.
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'returns' -> 'sets `SplatValue` to'


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Comment at: test/CodeGen/X86/pr34271.ll:7
+; CHECK:       # BB#0:
+; CHECK-NEXT:    paddd {{.*}}(%rip), %xmm0
+; CHECK-NEXT:    retq
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The previous version of the generated code had a plausible instruction sequence that ultimately did the wrong thing... Is it possible to actually check the values being added here?


https://reviews.llvm.org/D36996